Figure 9. Proposed cardioprotective mechanisms that could lead to increase cGMP.

The expression of natriuretic peptides could increase “particulate” cGMP pool, and the activation of AMPK, subsequent to increased PDE4 activity, could increase “soluble” cGMP pool through enhanced NO bioavailability. These increases in cGMP could also have effects on PDE activities: “particulate” cGMP may contribute to further increase PDE2 activation and “soluble” cGMP may further activate PDE5, enhancing even more cGMP hydrolysis.